Well, the implication (and I'm not saying this is right) is that to Google it's only worth $1k to have this brought to their attention by a white hat, versus finding out by exploitation.
Which means that they have zero concern from this incident about reputational damage to themselves or their browser. That's pretty good circumstantial evidence of a monopolistic practice, when you can safely assume that there's effectively no difference to your bottom line if your software is hacked.
But google is also a monopsony. There isn't anyone else the researcher can ethically sell it to. They just have to take whatever bounty google decides to pay.
I'm just saying it's more evidence that Google should be broken up.